Project Summary This proposal focuses on the development of new clinical measures of atrial shape for better individualized patient care of atrial fibrillation and advances the state-of-the art in computational methods for the statistical analysis of shape in clinical image data. Atrial fibrillation (AF) is the most common cardiac arrhythmia in adults, with over 400,000 U.S. hospital admissions per year, annual costs in the U.S. of $6-7 billion, and an almost two-fold increase in the risk of mortality. We will develop and test new cardiac shape-based predictors of AF outcomes in a large patient population, including patients enrolled in the fully-funded multicenter DECAAF II clinical trial. This proposal will impact clinical science and standards of care for AF patients through (1) the development of a new MRI-based measure of dynamic cardiac shape and associated deformations over the cardiac cycle and investigation of the dynamic (4D) structural changes to the atria after catheter ablation; (2) the development of shape-based predictors of AF treatment outcomes and risk factors for stroke; and (3) shape analysis of the atria and prospective evaluation of shape-based predictive indices in the DECAAF II clinical trial population. Technological contributions of this work will impact the field of biomedical shape analysis through the development of methods for analysis of spatiotemporal (4D) anatomical shape and the development of more powerful modeling algorithms for the highly variable anatomy of the heart. This project combines the clinical experience and research infrastructure of the University of Utah's Comprehensive Arrhythmia Research and Management (CARMA) Center with the computational resources and expertise of the Scientific Computing and Imaging (SCI) Institute and leverages our unique access to a large cohort of MRI image data from AF patients enrolled in the multicenter DECAAF II clinical trial. Our team consists of an accomplished mix of computer scientists, electrophysiologists, and MRI physicists.